There are many different types of commercially available crop spraying devices. Traditionally, these devices are mounted onto the rear end of a standard farm tractor. The controls for the spray device are mounted directly on the spray device and after manually initiating operation of the spraying device, the operator begins driving the tractor which carries the spray device. For any adjustments of the spray arrangement, the tractor must be stopped and the spray device manually altered.
Most spray devices distribute small droplets of chemicals. These small droplets provides coverage of the crop but are prone to drift in windy conditions so as to leave untreated areas of a field.
In spraying devices providing large droplets of chemicals, these droplets are less sensitive to drift but are not as easily retained by leaf surfaces. The large droplets therefore, may run off the target and also may burn the foliage.